The invention has for its subject a scraping device for floor and surface cleaning machines.
As is known, floors and surfaces, whether located outdoors or indoors at industrial establishments, are scraped clean by means of purposely designed machines which only act on the ground through a scraping assembly, or alternatively, by means of sweeping machines mounting a scraping assembly on the front.
The last-named assembly is provided with metal bristles, and has the function of raising as by scraping dirt cakes stuck to the ground surface to leave debris which is subsequently picked up and taken away.
A scraping assembly usually includes several scraping brushes having specially hard bristles, generally made of steel, and a bell-shaped element facing the ground and adhering on the same which is effective to withhold the loosened dirt.
On scraping devices or assemblies of known design, said bell-shaped element has the following features: it carries the scraping brushes, is driven of rotary motion, and is held with its edges in contact with the ground.
As an example, this Applicant has already made a scraping assembly in which said bell-shaped element centrally supports three rotary brushes, and carries along its edges a skirt in direct contact with the ground to prevent scattering of the removed particles. The brushes are rotated by means of a belt extending between the brushes and the bell top.
Further, the bell is rotated about its center axis, thus imparting an orbital movement to the rotary brushes which, when combined with the rotary movement, improves the effectiveness thereof. However, the known scraping devices or assemblies have not been quite effective in all occasions, and the same exhibit some important deficiencies.
A first problem encountered has been the build-up of dirt and dust in the drive mechanism to the scraping brushes, which may result in fast deterioration of the efficiency of the same.
Another problem encountered is that the aforesaid bell-shaped element not always achieves close adhesion to the ground in the known types, and accordingly, an effective seal due to the scraping brush supporting function it is to serve.
In fact, a possible obstruction met across the floor by the brushes may result in the brushes being locally raised off the floor surface together with the bell-shaped element. In that case, a section of the bell-shaped element edge contacting the ground is apt to be raised and let out some of the scraped debris.
It has been pointed out already that the bell-shaped element is usually driven rotatively to also impart an orbiting movement to the scraping brushes, which is effective to improve their scraping action. This movement is, however, hindered and slowed down in part by the friction arising from the bell-shaped element contact with the ground.
It is also observed that the rotary motion of the bell causes rapid wear of the elastic skirt or strip or bristle array mounted at the bottom of the bell-shaped element in order to withhold the debris scraped off more positively within it.